Sulfur-halogen compound



Patented July 10, 1951 Harry W. Rudel, Roselle Park, N. J assignor to Standard Oil Development Company, a corporationof Delaware.

No Drawing. Original application December 29,

1945, Serial No. 638,433. Divided" and this application October 20, 1048', Serial No. 55,641

3 Claims.

The present invention relates to sulfur-halo- Q gen compounds and particularly to the reaction products of thiocarbamates and. halogenatedhydrocarbons which have utility as extreme pressure additives for lubricating oils, and other uses in hydrocarbon polymers such as. natural and synthetic rubbers, and thelike. This. application is a division of my copending application Serial No. 638,433, filed December 29, 1945, now Patent No. 2,491,772 dated December 20, 1949, which claims an extreme pressure lubricant. The present invention relates to a composition per se which forms an active ingredient of such a lubricant.

In the prior art, various additives have been suggested to improve the film strength of mineral lubricating oils. Among the many E. P. additives heretofore recommended, those hydrocarbon derivatives containi-ng both active halogen and active sulfur have proved themselves to be very eiiective in increasing the loadbearing characteristics of mineral lubricating oil. Even though these sulfur-halogen compounds are exceedingly successful as E. P. additives, many of them have one characteristic which detracts from their acceptability. This characteristic is that these sulfur-halogen compounds tend to be somewhat unstable during storage, especially at temperatures above 100 F., liberating a hydrohalogen acid which is corrosive to metal containers. Such sulfur-halogen compounds are frequently too corrosive for use with certain types of bearings. Attempts have been made to overcome this excessive corrosiveness of: sulfurhalogen compounds by the use of inhibitors but without much success. While the use of inhibitors is somewhat successful in delaying the appearance of evidence of the corrosiveness of sulfur-halogen E. P. additives, they are often objectionable for the reason that they react with the additive or its decomposition products to give insoluble precipitates; Such reaction both detracts from the quality of the E. P. additive and destroys. the inhibitor.

An object of the present invention is the production of a novel, less corrosive type of sulfurhalogen compound. Another object is an improvement in E. P. lubricants. These and other objects will be apparent to those skilled in the art upon reading the following description.

The present invention is based upon the dis.- covery that the reactionv product of a chlorinated hydrocarbon containing active chlorine andan alkali metal salt of alkyl. or aryl dithiocarbamic acid, which may also be designated as alkyl or aryl-substituted alkali metal dithioaminoformate, is an oil-soluble compound having the property in oil solution of increasing the loadbearing characteristics of a mineral lubricating oil, and is stable during storage and relatively non-corrosive to metals. This reaction is illustrated'by the fOllOWiIlg equation:

RR'NCSSMet-l-R' 'Halz RR" NCSSR' Hahn-1 MetHal wherein R is an alkyl, cycloalkyl, aryl, aralkyl or alkaryl radical such as methyl, ethyl, propyl, amyl; cyclopentyl, cyclohexyl, or phenyl, benzyl, xylyl, etc. or a heterocyclic nitrogen-containing radical, such as piperidi-ne; R is hydrogen or a hydrocarbon radical such as alkyl, cycloalkyl, aryl, aralky-l, alkaryl, etc. R is a hydrocarbon residue derived from a petroleum mineral oil distillate such as paraifin waX, kerosene and aromatic petroleum fractions having from 8 to 30 carbon atoms to the molecule; Met is an alkali metal such as sodium, potassium, lithium, etc.; Hal is one of the halogens such as chlorine, bromine or iodine, of which chlorine is preferred and a: is a positive number of suificient magnitude that the weight per cent of halogen in the compound R'H'ah will range between 5 and preferably 30-40%, the final reaction product containing 5 to 40%, preferably 25 to 35% by weight of halogen. The value of x will therefore normally range between 2 and 5. The reaction may be carried out in the presence of a ketone solvent such as methyl ethyl ketone or acetone, although any other organic solvent, except alcohol, which'is capable of dissolving the carbamate, may be used, and at the reflux temperature of the particular solvent employed. After the reaction is complete, which generally requiresv from 1-3 hours, the reaction mixture is filtered to remove inorganic salts, after which the solvent is recovered by distillation and the product is refiltered to remove any residual inorganic salts' that may be present.

The halogenated hydrocarbon represented by Rl'Hahwhich may be a halogenated parafiin wax, kerosene or aromatic petroleum fraction is made by halogenating the hydrocarbon selected until on, a weight percentage basis the halogen content of the halogenated hydrocarbon ranges from about 5% to as. much as 50%. One example of a suitable halogenated hydrocarbon is one made by chlorinating kerosene to a chlorine content of about 40%, by passing chlorine through kerosome. at atmospheric pressure and a temperature of: about,1,55f 20.0f F. for 3. hours. The time required to suificiently chlorinate a petroleum mineral oil distillate under these conditions of temperature and pressure will range from about 30 minutes to hours. Within the range specified, the chlorine content of the chlorinated hydrocarbon may be varied to accommodate any previously determined sulfur-chlorine requirements in the final product.

The alkali metal salt of the hydrocarbon substituted dithiocarbamic acid is made by reacting a primary or secondary amine, carbon disulfide and alkali metal hydroxide according to the following equation:

In this formula the radicals R and R possess the same designations as were ascribed to R and R in the preceding formula illustrating the reaction between the carbamate salt and the halogenated hydrocarbon. The reaction is carried out by suspending stoichiometric amounts of amine and caustic in a solvent such as methyl ethyl ketone, which suspension is then cooled in an ice bath or other equivalent cooling means, and

carbon disulfide is then added slowly with agitation. Since the reaction is exothermic, the carbon disulfide must be added cautiously so as to maintain the reactants at a low temperature and prevent undue volatilization of the carbon disulfide. In view of the fact that carbon disulfide is a highly volatile liquid, some excess, up to about over that theoretically required, may be used without any harmful effects, for the purpose of compensating for any carbon disulfide lost through volatilization.

The substituted dithiocarbamic halogenated esters, containing from about 2 to 10% of sulfur and preferably 25 to 35% of chlorine, resulting from the reaction between the alkali metal salt of the substituted dithiocarbamic acid and the chlorinated hydrocarbon can then be blended in amounts ranging from 2 to 30% by weight, based on the total composition, preferably about 10%, in a mineral lubricating oil to yield an extreme pressure lubricant. In compounding such an extreme pressure lubricant, any of the numerous types of low pour point lubricating oils may be used; it is preferred, however, to use a Pennsyl- Vania type oil having a viscosity in the range of from about 50 to about 150 seconds S. U. V. at 210 F. and a cold test below 0 F. The following examples will serve to illustrate specific embodiments of the invention:

EXAMPLE 1 20 parts by weight sodium hydroxide 42.6 parts by weight piperidine 43.2 parts by weight carbon disulfide 407 parts by weight chlorinated kerosene containing 39.8% of chlorine The sodium hydroxide in powdered form was suspended in 250 cc. of methyl ethyl ketone in a reactor equipped with a stirrer and the piperidine was then added, after which the mixture was chilled in an ice bath. The carbon disulfide was then added dropwise and the addition of the carbon disulfide was accompanied by a vigorous exothermic reaction, yielding, after the reaction had subsided, a heavy yellow suspension of sodium piperidyl dithioformate in the solvent. The chlorinated kerosene and 250 cc. additional methyl ethyl ketone were placed in a separate reactor equipped with a reflux condenser; the heavy yellow suspension was then added to the chlorinated kerosene in methyl ethyl ketone and the 4 whole refluxed for 2 hours. The reaction mixture was then cooled and filtered to remove sodium chloride and the filtrate distilled under a reduced pressure of 37 mm. to remove the methyl ethyl ketone. The residue from the distillation was again filtered to take out any last traces of sodium chloride. 435 parts by weight of a product containing 4.9% sulfur and 31.2% chlorine were obtained. A 10% blend of this product in a mineral lubricating oil of 45 seconds vis. at 210 F. carried a full shock load of 15 weights in the Almen test as compared with 3 weights carried by the straight mineral oil. The reaction product in this example may be appropriately described as a piperidyl dithioformic chloroalkyl ester where the ester-forming group is chlorinated kerosene. As previously indicated, this group may be a halogenated paraffin Wax or a halogenated aromatic petroleum fraction instead of kerosene is desired.

EXAMPLE 2 20 parts by weight sodium hydroxide 42.5 parts by weight carbon disulfide 78.7 parts by weight diamyl amine 407 parts by weight chlorinated kerosene containing 39.8% of chlorine The carbon disulfide was reacted with the caustic and amine in the same manner as described in Example 1, resulting in a clear yellow solution which was then refluxed with the chlorinated kerosene for 2 hours and the product isolated. 485 parts by weight of a product containing 5.3% of sulfur and 28.6% chlorine was obtained; A 10% blend of this product in minineral lubricating oil carried a full shock load of 15 weights in the Almen test. The composition thus formed may be considered to be a diamyl dithiocarbamic chloroalkyl ester where the esterforming group is chlorinated kerosene. Instead of chlorinated kerosene, as previously indicated, halogenated paraffin wax or halogenated aromatic petroleum fractions may be used. More specifically, a chlorinated pentadecyl hydrocarbon may be used in lieu of or as a part of the chlorinated kerosene in which case the reaction product would comprise or consist of diamyl dithiocarbamic pentadecyl ester.

EXAMPLE 3 20 parts by weight sodium hydroxide 43.5 Parts by weight carbon disulfide 62.1 parts mixed xylidines 05 parts of chlorinated kerosene containing 39.8% of chlorine The caustic, xylidines and carbon disulfide were reacted in the presence of methyl ethyl ketone as described in Example 1, yielding a heavy yellow suspension which was refluxed with the chlorinated kerosene in methyl ethyl ketone. After removal of the solvent and inorganic salts, 449 parts of a product containing 3.4% sulfur and 30.4% chlorine was obtained. A blend of 10% of this product in mineral lubricating oil (45 vis. at 210 F.) carried a full shock load of 15 weights in the Almen test. As in Examples 1 and 2 above, other halogenated hydrocarbons may obviously be substituted for chlorinated kerosene.

To illustrate the improved corrosion characteristics of the compounds of the present invention, 10% blends of these products in a highly refined mineral lubricating oil (45 seconds vis. at 210 F.) were made up and tested according to the following procedure. 200 cc. of the blend and 2 cc. of water were vigorously agitated for 3 minutes. A Timken cup and an Almen pin were then placed in the lubricant and the lubricant stored in an oven at 120 F. for 48-hours at which time the extent of corrosion was noted. The results of these tests are shown in the following table.

Table Extent of corrosion Lubricating oil+10 commercial extreme pressure additivek. Marked Lubricating oil-{40% of the product made in Example 1 Very slight Lubricating oil+10% of the product made in Example 2 Slight stain Lubricating oil+10% of the product made in Example 3 Slight stain l Commercial extreme pressure additive containing sulfur and chlorine, but no nitrogen.

What is claimed is:

1. As a composition of matter, piperidyl dithioformic chloro-alkyl ester, where the ester-forming group is chlorinated of 5 to 50 chlorine content by weight kerosene.

2. As a composition of matter, a product having the general formula XCSSR"Halz, in which X is selected from the group consisting of piperidine and radicals RRN, R being a hydrocarbon radical selected from the group consisting of alkyl, cycloalkyl, aryl, alkaryl, and aralkyl substituents and R being selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl, alkaryl and aralkyl substituents; R" is a hydrocarbon radical selected from the group consisting of kerosene and wax, a: is a positive number of suflicient magnitude to make the halogen equal to from 5 to weight per cent of the molecule.

3. As a composition of matter, diamyl dithiocarbamic chloroalkyl ester, wherein the ester forming group is chlorinated kerosene of 5 to chlorine content by weight.

I HARRY W. RUDEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,396,487 Blake Mar. 12, 1946 2,404,446 Lieber et a1. July 23, 1946 2,491,772 Rude] Dec. 20, 1949 

2. AS A COMPOSITION OF MATTER, A PRODUCT HAVING THE GENERAL FORMULA XCSSR''''HALX, IN WHICH X IS SELECTED FROM THE GROUP CONSISTING OF PIPERIDINE AND RADICALS RR''N, R BEING A HYDROCARBON RADICAL SELECTED FROM THE GROUP CONSISTING OF ALKYL, CYCLOALKYL, ARYL, ALKARYL, AND ARALKYL SUBSTITUENTS AND R'' BEING SELECTED FROM THE GROUP CONSISTING OF HYDROGEN, ALKYL, CYCLOALKYL, ARYL, ALKARYL AND ARALKYL SUBSTITUENTS; R'''' IS A HYDROCARBON RADICAL SELECTED FROM THE GROUP CONSISTING OF KEROSENE AND WAX, X IS A POSITIVE NUMBER OF SUFFICIENT MAGNITUDE TO MAKE THE HALOGEN EQUAL OF FROM 5 TO 40 WEIGHT PER CENT OF THE MOLECULE. 